According to Ripple's policy, a minimum of 1 XRP is required to activate a Ripple wallet address. To activate your Ripple address, please send 1 XRP or more to your Ripple address in the D'CENT Wallet.
Go to the Ripple Account Usage Guide >>
Once your Ripple wallet address is activated, the 1 XRP used for activation will be permanently locked in your Ripple wallet address and cannot be reversed or used again. This means that you need to send XRP excluding the locked 1 XRP.
(Your balance before sending - (amount to send + fee) >= 1 XRP)
In addition, if you have added trustlines, 0.2 XRP will be locked up for each additional account, so please keep this in mind when making transactions.